Implementing a cross browser HTML5 pop
up calendar control

HTML5's <input type="date" /> element (and its variants such
as "datetime") is a great time saver when you need to add date related
controls to your forms. However, until all the major browsers support these
new elements, you still have to supply an alternate solution for the other
browsers. Putting theory into practice now, lets create a sample form that
uses HTML5's date control where it's supported, and fall back to jQuery UI's
Date Picker
widget where it's not:

In browsers that support HTML5's <input type="date" /> element, a
native calendar will pop up, while in other browsers, a custom jQuery date
picker instead. To maximize the benefits to the former group, we only load
the .js files associated with the custom jQuery Date Picker in those
browsers that do not support HTML5's intrinsic calendar control. A nice
compromise in a currently uncompromising browser landscape.